Process of manufacturing so, gas



Marh 7, 1933.

|. HECHENBLEIKNER PROCESS OF MANUFACTURING S02 GAS Filed Jan. 27, 1932 FOOD 1MP Lu um MIDWWMWE Poon do .53! macaw v INVENTOR INGENUIN HECHENBLEIKNER ATTORNEYS mu STATES P NT ounce 01' CHARLOTTE, HOBTH CAROLINA, ABSIGN OB TO CHEMI- Lmxnnn, our. consrnuorron conromnon, on mourn, 1mm senor-nu, A comm- TEON E DELAWARE PROCESS OF MANUFACTURING 50, GAS

Application mes Jennary 27, 1832. serial No. 589,099.

This invention relates to a method of treating acid sludge obtained in the refining of petroleum, tor and other organic materials, and relates more particularly to an improved 5 method for producing sulphurous acid gas and an acid-tree fuel from ecid sludge; and has special reference to the provision of improvements in the process of treating acid sludge set forth in my co ending application Serial No. 568,050, file-d Set. 10, 1931.

In the process set t'oflh inmy said copending application, ecid sludge is subjected in a retort to the action of hot combustion gases so that the organic matter of the sludge is made to react upon the sulphuric acid or its compounds in the sludge to convert the some to 3G gas which'is removed from the sphere of reaction. The combustion gases are generated in a furnace; and the ucid sludge in the retort is preferably directl heated with these combustion gases. 16y t e reaction in the retort, thesulphuric scid end its compounds in the sludge are reduced to an S0,;

gss substantially free oi impurities, which is produced in such a. condition that it may be readily and eficiently converted in contact or'cetslytic apparatus to sulphuric anhydride end sulphuric acid. In addition to the obtaining of the SU product there results the a granular sludge residue in the form of e very desirable fuel of on acidiree character having a high volatile content.

The combustion gases employed in the process and generated in the furnace may be obtained from a, variety of sources and may be produced, for example, from the burning of natural gas, oil, powdered cosh-coke, or other heat producing materials, Preferably the free oxygen content in the reaction utmosphere oi the acid sludge retort should be below 10% by volume and preferably between to 6%; and this is obtained by controlling the oxygen content or proportion in the combustion 5 operate s. large furnace with a low oxygen tort, and a. control of the strength gases. However, in order to content using natural gas, oil, pulverized carbonaceous residue or pulverized coal, such high temperatures are developed. in the furnace that it is difficult to maintain furnace linings without the use of expensive cooling such as water well construction, and furthermore there is'more than a little den 1 of undesirably overheating the acid slu go as it moves throughthe retort or converter.

I have empirically found that if part of the SO ularly after being cooled and scrubbedbe rte-circulated in the system with the hot combustion gases, as by being introduced in and admixed with the fuel of the furnace, all danger of burning out furnace linings is eflectively obviated, end that furthermore the possibility of overheating the sludge is effectively minimized. The recirculation of part of the generated S0 gas results in other important advantages in the process. Oil

vapors remaining in the gases are consumed operator a. further direct control of the temacid sludge reof gas to be produced, so that the operator may compensste for variations in the acid content of sludges such-as are bound to occur in the operation of e plant used in connection with peretures in the furnace and s refinery. There also results "a. combustion gas low in carbon and thus more suitable for use in decomposing acid sludge. The prime object of the present invention therefore resides in the provision of the improved process of treating acid sludge whereby S is generated, and wherein a part of the generated SO gas is thus re circuluted in the system for accomplishing these: results.

To the accomplishment-of these object'send 2 gas generated in the retort, purticother objects as will appear hereinz'iftig the J99 and the steps of the processes hereinafter more particularly described and sought to be defined in the claims, reference being had to the accompanying drawing, which shows a front elevational view of the apparatus which may he used in the practice of the process.

As set forth in my said copending application Serial No. 568,050, the process steps of the resent invention may be suitablypractics in a retort apparatus such as shown in the drawin wherein a body of petroleum or acid slu go is directly heated by hotcombustion gases in an elongated drum-she ed retort A, the combustion gases generate in a furnace B being introduced under suitable pressure into the drum retort A.

The retort A preferably comprises a cylinder or drum enerally designated as 10 made of iron or steel which if desired may he outwardly covered with a heat insulating medium. The dill is preferably interiorly subdivided by me of one or more annular members such as 1% into a plurality of separate and intercounicating compartments, two of which are exemplified in the drawing. 1 The dr retort 10 is provided at its opposite ends with reduced cylinder sections it and 15' respectively which serve for the ingress and egress of the reacting constituents and resultin products;

' point for the feed slud In the preferred practice the process the sludge charge in the retort is cause to flow through the compartments thereof and is thoroughly and continuously agitated as it moves throu h the-compartments so that all parts of the c arge are progressively re-. acted and acted upon during theprocessing. To accomplish these ends, the drum retort is preferably mounted for rotation during operation. esirably, the sludge charge is more thoroughly agitated or kneaded by providmg flights interiorly of the compartments (which elevate and drop the sludge mass durmogl retort rotation) and by introducing iron r sor rails in the compartments which are .inturn elevatcd hy the flights and which drop onto the sludge actin to break up and pound the sludge and car onaceous residue as these are caused to how through the compartments and serving to prevent the same from caking, adhering to and huildin up on the walls of the retort and to facihtats the thorough anduniform treatment of the sludge body The cylindrical end section 14' of the retort A is'made to serve as the intake or'entrant end for combustion gases generated in the furnace B and the expulsion end for the carbonaceous residue produced, while the opposite cylindrical end section 15' of the retort is made to serve as the intake or entrant and as-the exit or 02 s erated in expulsion end for the .23. place the final breaking up of the carbonaceous residue with further applied heating,

accuses the retort Accordingly the end section it is made to receive and communicate with the usual nozzle of the combustion apparatus or furnace B and is made to communicate with a hopper 21 forming part of the furnace structure .for the discharge of the carbonaceous residue, which hopper is sealed at the bottom by means of a slide door or the like. The end section 15' is in turn made to receive the sludge pipe 22' and is made to commu-7 nicate with the gas outlet 23. Since the retort chamber 10 is rotatable, the joints between the retort A and the combustion furnace B at one end, and those between the retort and the gas outlet 23 a the other end,

may be suitably packed with material such as asbestos or theli e. It will be understood that it is highly d sirable to make these joints air-tight so as to prevent the ingress or atmospheric air into the retort at either end or the loss of gases from the retort. I

In the operation of the system thus far described, a relatively weak teed slud e is introduced into the retort A throilgh t e pipe 22' and into the hody'oi sludge in the retort under treatment, which sludge body is thoroughly agitated as it is rotational y moved with the retort andas the sludge body progressively flows through the rotary compartments to the residue discharge end 14 of the V retort. Hot combustion gases generated in the furnace B are introduc (1 into the retort thro h the end section 14 thereof and are cause to flow in the direction op osite to the 1 direction of movement of the s udge body. In the operation of the system, the combustion gas flow and the flow of the feed sludge are controlled so as to create a number of reaction zones in the retort A, all as set forth with eater particularit in my aforesaid copening'application erial No. 568,050. One or more of these zones is or are maintained at a temperature ran e for reacting the sludge to reduce the H compounds thereof to S0 which latter is withdrawn from the retort at the gas outlet In another reaction zone there takes which residue is reduced to a granular acidiree fuel having a high volatile content and which is withdrawn from the system at the fuel outlet hopper 21".

oilboots 29 and 30. Here also 0 content or 310 In the further operation of the process, the mil may be removed any small traces of S0 if any are formed in the retort. *The condenser serves to cool the S0 gas to a low temperature which is substantially atmospheric temperature, and whichmore specifically is about 100 F. If desired, in order to prevent an undue rise inthe presure in the plant or system, a ressure relief valve such as 31 may be emp eyed following the condenser 26. I

As aforesaid, the combustion gases employed may be obtained from a variety of sources and may be produced, for example, from the burning of natural gas, oil, powdered coal, coho or other neat producing rnoteriols; and preferably the generated cornhustion gases should contain or low oxygen content desirably below 16% by volume and pretershly between2 to 6%. l have found that the control of the oxygen content in the combustion gases and in the reaction atmosphere of the retort. is important in producing :2. number of edventsgeous results in the procsee. The presence of free oxygen is, I believe, a factor in inhibiting the formation of H S gas in the retort when it is operated st the desired temperature range and is also 8; factor in shooting complete combustion of the gases; and the maintenance of the low pro. I believe, a factor portion of free oxygen is, in glvzn rise to a reaction atmosphere in the retort w erein the desired reduction and conversion of the sulphur containing compounds to S0 is efiected. Alsowith a. low oxygen content danger of fires is obviated and oxidation of the hydrocarbons in the acid sludge is The restriction of the free oxygen content in theretort is, I believe, also a factor in avoiding conversion of S0 to S0, in the retort. The oxygen content of the S0 gas leaving the condenwr 26 being insuflicicnt or subscquent conversion (where the S0 gas is subsequently converted to sulphuric anhydride and sulphuric acid), oxygen or air is introduced at 3% into the gas line and admixed with the produced S0 gas. 'As set forth in my'copending application Serial No.

575,549,, to contactmethod of sulphuric acid manufacture, tiled Nov. 17,1931, the air and S0 at this point of the system are so admixed as to obtain a ratio of oxygen to S0,, entering I the converter of the order-of Let to l.

.When operating the furnace with a low oxygen contont'usingony of the fuels aforementioned, the temperatures developed in the ace are so high as to render it diificult to maintain furnace linings without the use ofexpensive cooling equipment. Further more, as aforementioned, there is more than a little danger of undesirably overheating the acid sludge as it or converter. To

obviate the danger of burning out furnace linings and to minimize the possibility of overheating the sludge, a part of the SQ, gas generated in the retort is,

separate blower 38.

moves through the retort v conversion; The $0 gas is re-introduoed into the system, preferably by being ad fuel and more specifically mixed with the with the air usedin the furnace. To accomplish these results, I provide a return gas line 33 connected at one end to the pipe 34% at a point therein in advance of the air inlet 32 and connected at the other end to the furnace B at the air intake end thereof. The said gas line 33 is controlled in any suitable manner, as by a valve 36, and is provided, with a gas re-circulating blower 37". The air inlet 35 of the furnace may be provided with 2 turned. is regulated so as to produce a temperhture of about 2000 F. for the combustion gases leaving the furnace B. The corn trol is such that the reaction gases leaving the gas outlet of the rotary retort A have temperatures of from 240 to 260 F.

By thus rel-circulating part of the cooled S9 ge s with the hot combustion gases, and more particularly by thus admixing the cooled S0 gas with the fuel in the furnace temperatures may be reduced and controlled. The temperaturesin the furnace and the retort are thereby controlled to maintain the integrity of the furnace linings and to maintain the desired conditions in the retort. A strong S0 gas is produced in the retort due to using S0 gas as the diluent. Oil vapors remaining in the S0 gas which have not been removed by the condenser are consumed in the furnace, providing not only The amount of gas rethe furnace,

furnace places at the command of the operator a further direct control of the temperatures in addition to that provided by controlling the gas and sludge feed flows, as

well as a control of the strength of gas to be produced, so that the operator may compensate for variations in t e acid content of sludges such as are bound to occur in'the operation of a plant used in connection with a refinery. The use of the. S0 as a diluent also results in a combustion gas product low incarbon and thus more-suitable for use in decomposing the acid sludge.

The practice of my improved process, the operation of the. plant and the advantages incident thereto and resulting therefrom will inthe main be fully apparent from the above detailed description thereof. It will be further ap arent thatwhile ll prefer to embody all of 't e principles of the invention in the apparatus and process as described, these may,

be widely varied to employ any one or a number of these principles in combination to effect anyone or a number of the advantages flowing therefrom, all as l have attempted to define in the following claims.

ll claim:

1. The method of treating acid sludge which consists in subjecting acid sludge to hot combustion" gases whereby S0, gas is generated in -recirculating part of the generated SO, gas with the hot combustion 4. The method of treating acid sludge which consists in burnin a fuel to produce hot combustion gases, in subjectin acid sludge to the hot combustion gases w ereloy hot combustion gases, in subjectin S0 gas is generated and in admixing part of the generated S0, gas for the fuel.

5. The method of treating acid sludge which consists in burning a fuel to produce hot combustion gases, in subjectin acid sludge to the hot combustion gases w ereby SU gas is generated, in cooling the generated 80, gas and in admixing part of the cooled 80, gas with the fuel.

6. The method of treating acid sludge which consists in burning a fuel to producgiL aci sludge to the hot combustion gases w ereby S0 gas is generated, in cooling and scrub- 5 in graduated temperature zones,

hing the generated S0 as, and in Ie-CilCUllating a part of the S5 gas by admixing the same with the air used with the fuel.

7. The method of recoverin or producing sulphur dioxide from acid slu go which consists in agitating a body of the s udge, in subjecting t e same directly to hot combustion gases to efiect a reaction of the slud e body with a consequent reduction of the su phuric acid content or compounds thereof to sulphur dioxide gas, in removing the sulphur dioxide gas from the sphere of reaction, and in recirculating a part of the sulphur dioxide gas with the combustion gases.

8. The method of recovering SO, and carbonaceous contents from sludge which conheating the sludge with combustion sists in gases and in carrying on the heat treatment at least one oil the zones Ming maintained at a m ture rune for reacting the slud e to reduce the H 3, content or compoun thereof to S0, and another zone bein maintained at a temperature range for the 2|. 1| a1 conditioning to a useful fuel of the carbonaceous content of the sludge, and in re-circulat a part of the S0,- with the combustion gases.

9. The method of treating acid slud e which consists in subjecting the sludge irectly to the treatment of combustion to reduce the H SO content or compounds thereof to S0,, in carrying on the treatment b flowing the combustion gases and the sliidge into contact with each other in. generall countercurrent directions, and in re-circu ating a part at the produced S0, with the combustion gases.

10. The method of recovering $0, from acid sludge which consists in flowing heated gases over an agitated body of the sludge in an elongated retort, the heated gases introduced at one end of the retort, in flowing feed sludge into the sludge body at the other end of the retort, in removing the solid residue of the sludge at the said one end of the retort, in withdrawing the genera $0, from said other end of the retort, in cooling the generated S0 and in re-circulating a part of the cooled S0, with the heated uses.

11. The method of treating said acid sludge which consists in subjecting acid sludge to the action of heated gases whereby S0 gas is generated and in re-circulating artof the generated SO, gas with the heat 1' ases.

12. The met od of treating acid sludge which consists in subjecting acid sludge to hot combustion gases whereby a moisture containing 8G gas is 1generated, in flowing the ge'nerated'SO gas t rough a condenser where moisture is condensed and the generated gas is cooled to a low temperature, and in re-circulating a part of the thus treated SO, gas with said hot combustion gases.

13. The method of treating acid sludge which consists in burning a fuel to produce hot combustion gases, in subjecting acid sludge directly to the hot combustion gases whereby a moisture containing 80, as is generated, in flowing the generated S 2 gas through a condenser where moisture is con densed and the generated gas is cooled to atmospheric temperature. and in admixing a part of the thus treated S0 gas with said fuel.

it. The method of generatin S0 gas which consists in subjecting aci sludge to hot combustion gases in a as atmosphere low in tree oxygen whereby 0 gas low in free oxygen is generated, the oxygen content of the gas atmosphere being maintained below 10%, and in re-circulating part of the generated SO, gas with thehot combustion gases.

15. The method ot-"generating gas baims which consists in burning a fuel in the presence of air to produce hot combustion gases, the oxygen content of the combustion gases being maintained below 10%, in subjecting acid sludge to the hot combustion gases whereby SO gas is generated, and in admixing part of the generated S0 gas with the air used with the fuel.

Signed at Charlotte, in the county of Mecklenburg and State of North Carolina,

this 8th day of January A. D'. 1932.

INGENUIN HECHENBLEIKNER. 

